dt-bindings: clock: fixed-factor: Drop Allwinner A10 compatible

This compatible is part of the legacy sunxi clock support, and has not
been used since commit 6b48644b1d29 ("ARM: gr8: Convert to CCU") in
October 2016. Now that the code for this compatible has been removed,
let's drop the compatible.

Signed-off-by: Samuel Holland <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Acked-by: Rob Herring <[e-mail]>
Signed-off-by: Stephen Boyd <[e-mail]>

Documentation/devicetree/bindings/clock/fixed-factor-clock.yaml

···
 properties:
   compatible:
     enum:
-      - allwinner,sun4i-a10-pll3-2x-clk
       - fixed-factor-clock
 
   "#clock-cells":